Whatever judgment one makes of their record, they are neither political novices nor leaders easily cowed by external pressure. Their longevity has endowed them with a deep institutional memory, a strong instinct for regime survival and a pragmatic understanding of the uses — and limits — of both coercion and compromise. As the Trump administration looks to extract itself from its war with Tehran, it must grapple with these realities. Neither war nor peace with the Islamic republic will come easily, regardless of who occupies the White House.

My father was a secular nationalist. He was neither drawn to the religiously inspired revolutionary message of Ayatollah Ruhollah Khomeini nor particularly supportive of Shah Mohammed Reza Pahlavi, whose rule, in his view, owed much to the C.I.A.-assisted coup of 1953. Despite his misgivings about both camps, he remained committed to his job. When oil workers across the country went on strike to cripple the shah’s government, my father continued reporting to work in his capacity as a senior official of the Oil Service Company of Iran, which supported the National Iranian Oil Company’s petroleum operations.

That decision ultimately made him a target. In the weeks before his death, my father started to receive threats from Mansouroun — “the Victorious Ones” — a militant Islamist guerrilla organization that viewed those who continued working in the oil industry as enemies of the revolutionary cause. In the foggy predawn hours of Dec. 23, 1978, just a few feet from our home, they ambushed my father as he drove to work, shooting him once in his chest and once in his hand. At the same time, several miles away, members of a closely allied Islamist guerrilla organization unleashed a hail of gunfire on the car of Mr. Grimm. Both men were killed.

The twin assassinations were a turning point for Iran. Mr. Grimm, the acting managing director of the Oil Service Company, was the only American killed during the revolutionary upheaval of 1978 and 1979. His murder triggered the evacuation of most foreign personnel employed in Iran’s oil industry, dealing a severe blow to production. According to figures from the U.S. Department of Energy, within three days of the murders, oil output plummeted from 3.2 million barrels per day to under 700,000. The economic paralysis of the shah’s regime was no longer a looming possibility. It was a fast-unfolding reality, hastened by a campaign of intimidation and violence waged by Islamist militants.

Stunned and disoriented, I returned to Iran to be with my family. Unlike my father, I had been sympathetic to the revolutionary cause as a teenager, even if I, too, was uneasy with its overtly religious overtones and symbolism. Now the revolution had just claimed my father’s life, leaving me to grapple with a tangle of grief, anger, sympathy and uncertainty. The modern world had not yet witnessed a successful theocratic revolution, and what was unfolding before my eyes was bewildering. One day I would visit my father’s grave; the next, I would stand among crowds observing revolutionary demonstrations in the streets.